Abu Al-Minhal said:"I asked Al-Bara bin 'Azib about money exchange. He said: 'Ask Zaid bin Arqam, for he is better than me and more knowledgeable.' So I asked Zaid and he said: 'Ask Al-Bara for he is better than me and more knowledgeable.' And they both said: 'The Messenger of Allah forbade (selling) silver for gold on credit."'
أَخْبَرَنَا أَحْمَدُ بْنُ عَبْدِ اللَّهِ بْنِ الْحَكَمِ، عَنْ مُحَمَّدٍ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ حَبِيبٍ، قَالَ سَمِعْتُ أَبَا الْمِنْهَالِ، قَالَ سَأَلْتُ الْبَرَاءَ بْنَ عَازِبٍ عَنِ الصَّرْفِ، فَقَالَ سَلْ زَيْدَ بْنَ أَرْقَمَ فَإِنَّهُ خَيْرٌ مِنِّي وَأَعْلَمُ . فَسَأَلْتُ زَيْدًا فَقَالَ سَلِ الْبَرَاءَ فَإِنَّهُ خَيْرٌ مِنِّي وَأَعْلَمُ فَقَالاَ جَمِيعًا نَهَى رَسُولُ اللَّهِ صلى الله عليه وسلم عَنِ الْوَرِقِ بِالذَّهَبِ دَيْنًا .
Nesai
The Book of Financial Transactions • Hadith 4577